Variable displacement swash plate type compressor

ABSTRACT

Provided is a variable displacement swash plate type compressor including a cylinder block having a plurality of cylinder bores, a front housing disposed in the front of the cylinder block to form a swash plate chamber, a drive shaft rotatably supported by the cylinder block, a lug plate disposed in the swash plate chamber of the front housing and fixed to the drive shaft, a rear housing disposed in the rear of the cylinder block to form a suction chamber and a discharge chamber in communication with the cylinder bores through suction/discharge valves, a swash plate rotated by the lug plate to vary its inclination angle, a spring supported between the lug plate and the swash plate, and pistons slidably engaged with the swash plate and reciprocally accommodated in the cylinder bores, characterized in that a power transmission groove is formed at a rear part of the lug plate opposite to the swash plate, a hooking projection inserted into the power transmission groove is formed at a front part of the swash plate opposite to the lug plate, and slide blocks are installed at a pin projecting from both sides of the hooking projection to be interposed between an inner side surface of the power transmission groove and an outer side surface of the hooking projection.

TECHNICAL FIELD

The present invention relates to a variable displacement swash plate type compressor, and more particularly, to a variable displacement swash plate type compressor capable of preventing direct contact between a swash plate and a lug plate to reduce friction therebetween and ensure smooth inclination movement.

BACKGROUND ART

A conventional swash plate type compressor is widely used for a compressor in an air conditioner of a vehicle. A disc-shaped swash plate is fixedly installed at a drive shaft, to which power of an engine is transmitted, with a certain inclination angle, to be rotated by the drive shaft. A plurality of pistons installed around the swash plate through the medium of a shoe reciprocates in a plurality of cylinder bores depending on rotation of the swash plate, thereby sucking, compressing and discharging a coolant gas.

Especially, in recent times, a variable displacement swash plate type compressor that has been proposed performs a precise temperature control by controlling a stroke of pistons using variation of an inclination angle of a swash plate depending on variation of thermal load, and reduces abrupt torque fluctuation of an engine due to continuous variation of the inclination angle to thereby improve ride comfort of a vehicle.

Korean Patent Registration No. 0529716 (Patentee: Doowon Technical College and Doowon Electronics, Co., Ltd.) discloses an example of the variable displacement swash plate type compressor, major components of which are shown in FIGS. 1 and 2.

As shown in the figures, the conventional variable displacement swash plate type compressor 1000 includes a cylinder block 110 having a plurality of cylinder bores 110 a parallelly formed at an inner periphery thereof in a longitudinal direction and constituting an outer part of the compressor, a front housing 120 disposed in the front of the cylinder block 110 to form a swash plate chamber 120 a, a drive shaft 140 rotatably supported by the cylinder block 110 and the front housing 120, a lug plate 180 disposed in the swash plate chamber 120 a of the front housing 120 and fixed to the drive shaft 140, a rear housing 130 having a suction chamber 132 and a discharge chamber 133 formed therein and disposed in the rear of the cylinder block 110, a swash plate 150 having a circular disc shape and rotated by the lug plate 180 to vary its inclination angle, a spring 170 supported between the lug plate 180 and the swash plate 150, and pistons 200 slidably coupled with the swash plate 150 through the medium of a shoe 201 and reciprocally accommodated in the cylinder bores 110 a.

The rear housing 130 includes the suction chamber 132 and the discharge chamber 133, and a valve plate 131 includes a suction port for communicating the cylinder bores 110 a with the suction chamber 132, and a discharge port 131 b for communicating the cylinder bores 110 a with the discharge chamber 133.

In addition, the suction port 131 a and the discharge port 131 b formed at the valve plate 131 include a suction valve (not shown) and a discharge valve (not shown) for opening and closing the suction port 131 a and the discharge port 131 b depending on pressure variation due to reciprocation of the pistons 180.

Further, a sleeve 300 is installed between the drive shaft 140 and an inner surface of an insert hole 150 a of the swash plate 150.

Meanwhile, a first hooking groove 182 is formed at a rear surface of the lug plate 180 opposite to the swash plate 150, guide surfaces 183 are formed at both sides of the first hooking groove 182, and second hooking grooves 184 are formed inside the guide surfaces 183 therealong.

In addition, a hooking projection 151 coupled with the first hooking groove 182 is formed at a front part of the swash plate 150 opposite to the lug plate 180, and a pin 152 relatively movable along the guide surfaces 183 and the second hooking grooves 184 of the lug plate 180 project from both sides of the hooking projection 184.

Therefore, when the compressor is actually operated, the first hooking groove 182 of the lug plate 180 is engaged with the hooking projection 151 of the swash plate 150 to transmit a rotational power.

Meanwhile, since the spring 170 is disposed between the rear surface of the lug plate 180 and the sleeve 300, the sleeve 300 is normally in contact with the swash plate 150 to maintain a minimum inclination angle.

However, in the conventional variable displacement swash plate type compressor, since the first hooking groove 182 of the lug plate 180 is engaged with the hooking projection 151 of the swash plate 150 to transmit a rotational power, and the pin 152 and the guide surfaces 183 slide along each other while maintaining compression force when the swash plate 150 is tilted during rotation, wearing between the swash plate 150 and the lug plate 180 may occur.

In addition, as shown, while the swash plate 150 may slide in a tilted direction when the pin 152 is guided along the guide surfaces 183 and the second grooves 184 of the lug plate 180 through bearings 153, since a friction force may be applied by the rotational power between the first hooking groove 182 of the lug plate 180 and the hooking projection 151 of the swash plate 150 during drive of the compressor, the swash plate may not smoothly slide.

The above problems are caused by the fact that a component for transmitting the rotational power is separated from a component for guiding the slide movement of the swash plate.

DISCLOSURE OF INVENTION Technical Problem

In order to solve the problem, it is an aspect of the present invention to provide a variable displacement swash plate type compressor capable of removing direct contact between a swash plate and a lug plate during rotation to ensure smooth slide movement of the swash plate and reduce wearing due to friction therebetween, thereby increasing durability.

Technical Solution

The foregoing and/or other objects of the present invention may be achieved by providing a variable displacement swash plate type compressor including a cylinder block having a plurality of cylinder bores, a front housing disposed in the front of the cylinder block to form a swash plate chamber, a drive shaft rotatably supported by the cylinder block, a lug plate disposed in the swash plate chamber of the front housing and fixed to the drive shaft, a rear housing disposed in the rear of the cylinder block to form a suction chamber and a discharge chamber in communication with the cylinder bores through suction/discharge valves, a swash plate rotated by the lug plate to vary its inclination angle, a spring supported between the lug plate and the swash plate, and pistons slidably engaged with the swash plate and reciprocally accommodated in the cylinder bores,

characterized in that a power transmission groove is formed at a rear part of the lug plate opposite to the swash plate, a hooking projection inserted into the power transmission groove is formed at a front part of the swash plate opposite to the lug plate, and slide blocks are installed at a pin projecting from both sides of the hooking projection to be interposed between an inner side surface of the power transmission groove and an outer side surface of the hooking projection.

Here, when seen from a side view, a rear surface of the power transmission groove in contact with periphery surfaces of the slide blocks may project toward the drive shaft in a tilted direction.

In addition, the rear surface of the power transmission groove may have two inclined guide surfaces for guiding movement of the periphery surfaces of the slide blocks, and a rear groove formed between the two inclined guide surfaces.

Further, the groove may be inclined along a rear surface inclination of the power transmission groove.

Furthermore, a sleeve may have a coupling hole through which the drive shaft is relatively movably inserted, and cylindrical guide projections formed at both sides of the coupling hole, and

guide grooves coupled with the guide projections of the sleeve may be formed at an inner surface of an insert hole of the swash plate.

In addition, an outer surface of the sleeve being faced with the insert hole of the swash plate may have a convex curved surface.

Further, the pin coupled with the slide blocks may have a cylindrical outer surface.

Furthermore, a stopper may be installed at the drive shaft behind the swash plate.

In addition, the spring may be disposed between a rear surface of the lug plate and a front surface of the sleeve.

Further, reinforcement ribs may be formed to cross a rear surface of the lug plate and opposite side surfaces of the power transmission groove.

Furthermore, grooves hooked by the pin may be formed at both inner side surfaces of the power transmission groove to prevent the swash plate from being lifted.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and advantages of the present invention will become apparent and more readily appreciated from the following description of exemplary embodiments, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a longitudinal cross-sectional view of a conventional variable displacement swash plate type compressor;

FIG. 2A is a front perspective view of a structure around a swash plate of FIG. 1;

FIG. 2B is a rear perspective view of a structure around the swash plate of FIG. 1;

FIG. 2C is a partially cut perspective view of a structure around the swash plate of FIG. 1;

FIG. 2D is an exploded perspective view of a structure around the swash plate of FIG. 1;

FIG. 3 is a longitudinal cross-sectional view of a variable displacement swash plate type compressor in accordance with the present invention;

FIG. 4A is a front perspective view of major components around a swash plate of FIG. 3;

FIG. 4B is a rear perspective view of major components around the swash plate of FIG. 3;

FIG. 5 is an exploded perspective view of FIG. 4A;

FIG. 6A is a partially cut perspective view of FIG. 4A in a minimum inclination angle position;

FIG. 6B is a partially cut perspective view of FIG. 4A in a maximum inclination angle position;

FIG. 7A is a side view of FIG. 6A;

FIG. 7B is a side view of FIG. 6B;

FIG. 8 is a perspective view of a lug plate of FIG. 5; and

FIG. 9 is a perspective view of a swash plate of FIG. 5.

BEST MODE FOR CARRYING OUT THE INVENTION

Reference will now be made in detail to exemplary embodiments of the present invention illustrated with reference to FIGS. 3 to 9.

As shown in the figures, a variable displacement swash plate type compressor 1000 includes a cylinder block 110 having a plurality of cylinder bores 110 a parallelly formed at an inner periphery thereof in a longitudinal direction and constituting an outer part of the compressor, a front housing 120 disposed in the front of the cylinder block 110 to form a swash plate chamber 120 a, a drive shaft 140 rotatably supported by the cylinder block 110 and the front housing 120, a lug plate 180 disposed in the swash plate chamber 120 a of the front housing 120 and fixed to the drive shaft 140, a rear housing 130 having a suction chamber 132 and a discharge chamber 133 formed therein and disposed in the rear of the cylinder block 110, a swash plate 150 having a circular disc shape and rotated by the lug plate 180 to vary its inclination angle, a spring 170 supported between the lug plate 180 and the swash plate 150, and pistons 200 slidably coupled with the swash plate 150 through the medium of a shoe 201 and reciprocally accommodated in the cylinder bores 110 a.

The rear housing 130 includes the suction chamber 132 and the discharge chamber 133, and a valve plate 131 includes a suction port 131 a for communicating the cylinder bores 110 a with the suction chamber 132, and a discharge port 131 b for communicating the cylinder bores 110 a with the discharge chamber 133.

In addition, the suction port 131 a and the discharge port 131 b formed at the valve plate 131 include a suction valve and a discharge valve for opening and closing the suction port 131 a and the discharge port 131 b depending on pressure variation due to reciprocation of the pistons 180.

In this embodiment, a power transmission groove 185 is formed at a rear part of the lug plate 180 opposite to the swash plate 150, and grooves 186 are formed at both inner side surfaces 185 b of the power transmission groove 185.

In addition, a hooking projection 151 inserted into the power transmission groove 185 is formed at a front part of the swash plate 150 opposite to the lug plate 180.

Further, a pin 152 projects from both side surfaces of the hooking projection 151 to be moved in the grooves 186, thereby preventing the swash plate 150 from being lifted. As shown, the pin 152 may be inserted into a hole formed in the hooking projection 151, or may be directly welded to the hooking projection 151.

Especially, slide blocks 155 are rotatably installed at the pin 152 to move along the power transmission groove 185. As shown, the slide blocks 155 have a circular shape, but are not limited thereto, as they may have various shapes such as a polygonal shape, and so on.

Specifically, the slide blocks 155 are interposed between inner side surfaces 185 b of the power transmission groove 185 of the lug plate 180 and outer surfaces of the hooking projection 151 to be guided along the inner side surfaces 185 b of the power transmission groove 185 during rotation of the drive shaft 140, thereby transmitting power.

In addition, when seen from a side view, a rear surface of the power transmission groove 185 projects toward the drive shaft 140 in a tilted direction, and periphery surfaces of the slide blocks are in contact with the rear surface of the power transmission groove 185 to be rotatably moved. In this case, the grooves 186 may be inclined along the rear surface of the power transmission groove 185 such that the swash plate 150 is smoothly moved in a tilted direction.

Further, the rear surface of the power transmission groove 185 may have two inclined guide surfaces 185 a along which the periphery surfaces of the slide blocks 155 move in a contact manner, and a rear groove 187 formed between the two inclined guide surfaces 185 a. That is, the rear surface of the power transmission groove 185 may have the two inclined guide surfaces 185 a, and the rear groove 187 formed therebetween.

Formation of the rear groove 187 may reduce weight of the lug plate 180 and prevent interference with the hooking projection 151 of the swash plate 150.

In addition, reinforcement ribs 188 may be formed to cross the rear surface of the lug plate 180 and opposite side surfaces of the power transmission groove 185 to prevent deformation thereof when a rotational power is transmitted by the slide blocks 155.

Meanwhile, a sleeve 300 is installed between the drive shaft 140 and an inner surface of an insert hole 150 a of the swash plate 150.

In this case, the sleeve 300 is relatively movably coupled with the drive shaft 140 in a longitudinal direction thereof. For this purpose, the sleeve 300 has a coupling hole 310.

In addition, the sleeve 300 is coupled with the inner surface of the insert hole 150 a of the swash plate 150. Moreover, the swash plate 150 is configured to relatively rotate with respect to the sleeve 300 in a tilted direction. For this purpose, guide projections 320 are formed at both sides of the coupling holes 310 of the sleeve 300, and guide grooves 159 coupled with the guide projections 320 of the sleeve 300 are formed at an inner surface of the insert hole 150 a of the swash plate 150.

In the drawings, the guide projections 320 have a cylindrical outer shape, but are not limited thereto, as they may have an oval column shape or a polygonal column shape.

In addition, an outer surface of the sleeve 300 being faced with the insert hole 150 a of the swash plate 150 has a convex curved surface. Therefore, the swash plate 150 can be readily moved in a tilted direction.

Meanwhile, the spring 170 is disposed between the rear surface of the lug plate 180 and the sleeve 300 to bias the sleeve 300 against the swash plate 150, thereby maintaining a minimum inclination angle of the swash plate. In addition, it is possible to prevent abrupt collision of the swash plate 150 with the lug plate 180 using the spring 170.

Hereinafter, operation of the embodiment will be described.

As shown in FIGS. 3 to 9, a rotational power is transmitted from an engine (not shown) through a pulley (not shown) to rotate the drive shaft 140. Therefore, the lug plate 180 for power transmission fixedly installed at the drive shaft 140 is rotated. In addition, at the same time, the rotational power is transmitted through the slide block 155 coupled with the power transmission groove 185 of the lug plate 180 to rotate the swash plate 150.

In addition, an initial angle of the swash plate 150 causes reciprocal movement of the shoe 201 and the pistons 200 in the cylinder such that a coolant gas is continuously sucked from the suction chamber 132 to be compressed in the bores 110 a and discharged from the discharge chamber 133. At this time, a flow rate of the discharged coolant gas is controlled by pressure regulation in the swash plate chamber using a pressure regulation valve (not shown).

When the pressure in the swash plate chamber 120 a is decreased, the swash plate 150 is inclined by a pressure difference between the swash plate chamber 120 a and the cylinder bores 110 a, and at the same time, the slide blocks 155 move along the inner side surfaces 185 b of the power transmission groove 185, and at the same time, the slide blocks 155 rollingly move along the inclined guide surfaces 185 a formed at a rear surface of the power transmission groove 185. That is, the slide blocks 155 roll along the inclined surfaces 185 a of the power transmission groove 185 and are guided by the inner side surfaces to transmit the power.

Therefore, it is possible to smoothly perform inclination movement of the swash plate 150.

Moreover, while one surfaces of the slide blocks 155 are in contact with the inner side surfaces of the power transmission groove 185 of the lug plate 180 to perform the inclination movement of the swash plate 150, since the slide blocks 155 are also rotated at the same time as the inclination movement, it is possible to remarkably reduce resistance against the inclination movement.

Eventually, side surfaces of the slide blocks 155 function as power transmission surfaces and guide surfaces, and periphery surfaces act as rolling movement surfaces to simultaneously perform guidance for power transmission and inclination movement.

Meanwhile when the inclination angle is continuously varied to form a maximum inclination angle, a lower end of the swash plate is in contact with the lug plate.

In addition, when rotation of the drive shaft is stopped, the swash plate is returned to its original position by the spring between the swash plate and the lug plate. In this case, a stopper 144 and a snap ring 145 may be installed at the drive shaft 140 to stop movement of the sleeve 300 and the swash plate 150.

Further, the spring 170 can prevent noise due to collision between the swash plate and the lug plate caused by return of the inclination angle and abrupt inclination between the lug plate and the swash plate.

INDUSTRIAL APPLICABILITY

As can be seen from the foregoing, slide blocks are disposed between a power transmission groove formed at a rear part of a lug plate and a hooking projection of a swash plate, and side surfaces of the slide blocks function as power transmission surfaces and periphery surfaces act as rolling movement surfaces, thereby more smoothly performing inclination movement than the conventional art.

In addition, rolling movement of the slide blocks can minimize wearing of the power transmission groove of the lug plate, thereby increasing durability.

Further, the slide blocks are interposed between the swash plate and the lug plate during driving of a compressor to prevent direct contact therebetween, thereby preventing friction between the swash plate and the lug plate due to direct contact.

Furthermore, when the hardness of slide blocks is smaller than the hardness of the swash plate and the lug plate, only worn slide block part needs to be replaced with a new one to readily perform maintenance and reduce cost. 

1. A variable displacement swash plate type compressor comprising: a cylinder block having a plurality of cylinder bores, a front housing disposed in the front of the cylinder block to form a swash plate chamber, a drive shaft rotatably supported by the cylinder block, a lug plate disposed in the swash plate chamber of the front housing and fixed to the drive shaft, a rear housing disposed in the rear of the cylinder block to form a suction chamber and a discharge chamber in communication with the cylinder bores through suction/discharge valves, a swash plate rotated by the lug plate to vary its inclination angle, a spring supported between the lug plate and the swash plate, and pistons slidably engaged with the swash plate and reciprocally accommodated in the cylinder bores, characterized in that a power transmission groove is formed at a rear part of the lug plate opposite to the swash plate, a hooking projection inserted into the power transmission groove is formed at a front part of the swash plate opposite to the lug plate, and slide blocks are installed at a pin projecting from both sides of the hooking projection to be interposed between an inner side surface of the power transmission groove and an outer side surface of the hooking projection.
 2. The variable displacement swash plate type compressor according to claim 1, wherein, when seen from a side view, a rear surface of the power transmission groove in contact with periphery surfaces of the slide blocks projects toward the drive shaft in a tilted direction.
 3. The variable displacement swash plate type compressor according to claim 2, wherein the rear surface of the power transmission groove has two inclined guide surfaces for guiding movement of the periphery surfaces of the slide blocks, and a rear groove formed between the two inclined guide surfaces.
 4. The variable displacement swash plate type compressor according to claim 2, wherein the groove is inclined along a rear surface inclination of the power transmission groove.
 5. The variable displacement swash plate type compressor according to claim 1, wherein a sleeve is disposed between the drive shaft and an inner surface of an insert hole of the swash plate to be reciprocally installed at the drive shaft, wherein the sleeve has a coupling hole through which the drive shaft is relatively movably inserted, and cylindrical guide projections formed at both sides of the coupling hole, and guide grooves coupled with the guide projections of the sleeve are formed at an inner surface of an insert hole of the swash plate.
 6. The variable displacement swash plate type compressor according to claim 5, wherein an outer surface of the sleeve being faced with the insert hole of the swash plate has a convex curved surface.
 7. The variable displacement swash plate type compressor according to claim 1, wherein the pin coupled with the slide blocks has a cylindrical outer surface.
 8. The variable displacement swash plate type compressor according to claim 1, wherein a stopper is installed at the drive shaft behind the swash plate.
 9. The variable displacement swash plate type compressor according to claim 5, wherein the spring is disposed between a rear surface of the lug plate and a front surface of the sleeve.
 10. The variable displacement swash plate type compressor according to claim 1, wherein reinforcement ribs are formed to cross a rear surface of the lug plate and opposite side surfaces of the power transmission groove.
 11. The variable displacement swash plate type compressor according to claim 1, wherein grooves hooked by the pin are formed at both inner side surfaces of the power transmission groove. 